The Story Behind Ford’s Ill-Fated 1968 Tunnel-Port 302

Students of the SCCA’s famed Trans-American Sedan series know how quickly it evolved from infancy in 1966 through the glory days of the ’70 season. The first year of competition saw Ford’s Mustang, in relatively modest form, win the championship over some very tough Chrysler competition. The ’67 Trans-Am season would prove just as difficult for Ford and the pseudo-factory-supported Shelby team, not only due to Chevrolet’s new Camaro entry but also because of in-house competition from sister-division Mercury’s Cougar. In the end, Mustang prevailed again, but a pitched battle with the factory Bud Moore Cougars wasn’t settled until the last race of the series. The Penske Camaro team was advancing so rapidly that Ford made dramatic changes to its program in the off-season in an attempt to stay ahead of the game for 1968. That ended up quite different than expected.

Chevrolet had jumped into the ’67 fray with a couple of inherent advantages over Ford. First was the creation of an engine that pretty well maximized the SCCA’s 5.0L limit, the 302-inch result of combining a 327’s 4.00-inch bore with a 283’s 3.00-inch stroke. Second, the small-block Chevy was endowed with better-flowing production cylinder heads than any small-block Ford heretofore. In hindsight, you could say Ford, Shelby, and Bud Moore had all done a remarkable job in commanding the ’67 series using 289s and GT40 cylinder heads. But with Mark Donahue and company winning the final two races of the season in Chevys, the writing was on the wall.

To counter the challenge as the ’68 season loomed, Ford came up with a 302-inch short-block of its own, then went over the top with all-new, no-expense-spared cylinder heads and associated intakes that were envisioned to best all comers. Inspiration for the heads came directly from the big-brother 427 Tunnel Port, a design that saw considerable success in NASCAR and international endurance racing. The result was the 302 Tunnel Port, the moniker for the engine being a reflection of the cylinder heads’ intake ports—big and round like a tunnel, with no regard for the limits that a pushrod normally imposes. Instead, some pushrods ran directly through the middle of the 2.2-inch-diameter ports inside brazed-in tubes that kept the intake charge where it belonged.

4/21An up-close view of a traditional Windsor head (left, a ported 351W), and a 302 Tunnel Port head shows the radically different architecture.

While the 302 Tunnel Port was born to race, SCCA homologation requirements meant that hundreds of engines would have to be built and sold in production cars to make the whole thing pass muster. Ford fans must have been dancing in the streets when they got the news in early 1968 through virtually every buff book on the planet. Magazine headlines for Ford’s mid-’68 debuts often paired the 428 Cobra Jet and 302 Tunnel Port, both being a sight for sore Blue Oval eyes. Two distinct versions of the Tunnel Port were slated, one as a homologation-worthy street piece and the other the full-race version. It seemed a ready stream of production and race parts would be available to make the small-block Ford the envy of the industry.

Then Ford got trounced in the ’68 Trans-Am series and the street Tunnel Port wasn’t installed in a single production vehicle. So what gives?

5/21It’s no surprise that Tunnel Port heads have been used by racers of all sorts, including drag racers. Randy Gillis is one such enthusiast, who prepped the street heads on his ’66 Shelby drag car. With a stout 331-inch short-block, a C4 auto trans, and 4.86 gears, Gillis was able to run mid 11s at almost 119 mph.

The Tunnel Port was an extremely high-rpm engine, lacking bottom-end grunt. Hank Lenox, lead engineer for the project, told HOT ROD in a recent interview, “At the time, my bosses at Ford felt horsepower won races, so the task was to create a head that made a big peak number. Even then I believed it was the wrong approach, since road racing requires a broad powerband and plenty of torque for coming out of the corners. The Tunnel Port worked well in a narrow, high-rpm range—actually more suited to the kind of rpm found in oval-track racing. I wasn’t surprised when the Trans-Am effort struggled.” Lenox should know, for in addition to the 302 Tunnel Port program, he worked in Ford’s in-house Indy and LeMans programs, designed the original GT40 head that the Trans-Am teams used a derivative of in 1967, and also contributed to the Gurney-Weslake heads that helped John Wyer’s GT40s win LeMans in ’68 and ’69.

Chuck Cantwell was the team engineer for Ford’s only factory Trans-Am team in 1968—the Shelby Racing Company—and explained many of the same issues about the nature of the 302 Tunnel Port. Cantwell says that 8,500-rpm shift points were commonplace, with occasional 9,000-rpm blasts—at least 1,000–1,500 revs higher than in 1967, and clearly exploring the limits of the reciprocating assembly, the GT40 four-bolt block, the valvetrain, and the oiling system. Still, there was a flash of brilliance for the Tunnel Port, and the street scene surely would have devoured something better than Ford’s only production offerings at the time—the pedestrian 289/302 head castings with their diminutive 1.78/1.45 valves. Too bad the program didn’t work as planned.

6/21Small-block Ford fans will see that the exhaust port on the Tunnel Port street head is noticeably different than traditional Windsors. Measurements taken at JBA Engines showed actual valve sizes on the street head to be 1.95/1.55, with a narrower centerline than the race head: 1.875 inches compared with 1.92 inches.

7/21Another Tunnel Port–powered vintage racer is this Shelby team car, owned and raced today by Ockerlund. Here being prepped at Canepa Design, the car was primarily driven by Horst Kwech in the ’68 Trans Am, but also by Parnelli Jones, Dan Gurney, David Pearson, and Alan Moffet.

The racing debut for the 302 Tunnel Port could hardly have been on a bigger stage: the ’68 24 Hours of Daytona. Cantwell recounts how the Shelby team was scrambling to prepare the new engine and cars for the event “right down to the wire.” Out of the box, the Shelby guys got it right, as Jerry Titus and Ronnie Bucknum drove their red No. 1 Mustang coupe to the Trans-Am victory, and Fourth overall behind a trifecta of prototype Porsches. Hour upon hour of running Daytona’s blend of road course and high-bank would have seemed the ultimate shakedown for the Tunnel Port, and an endorsement of its durability. Says Cantwell, “We ran the first two-thirds of the race pretty hard, but fortunately were able to take it a little easier for the last third as our competition had fallen far behind. It’s a good thing, too, as I don’t think the car had much left in it.”

Daytona proved the high-water mark for Ford’s Trans-Am program, as the reliability that seemed so strong went sideways in a hurry. The record for the 13-event season reveals only one race in which both Shelby team cars finished—and that 8th and 11th Place performance at Meadowdale International Raceway is an indicator that plenty had gone wrong during the outing. Also, three races saw no team cars finish, clearly problematic when trying to score points toward a manufacturers’ title. To be fair, not every DNF was engine-related, but a freakishly high number were inarguably the result of blown motors.

Interestingly, and without an explanation we could uncover, Ford dictated early in the ’68 season that 302 Tunnel Ports would be built in-house in Dearborn. Cantwell explains that Shelby American’s engine shop had built the race engines for the ’67 team Mustangs, just as it had for countless competition Cobras and GT350s. The first three races of 1968 saw no change in those plans, but beginning with race four at Lime Rock, the engines came direct from Ford (a lone exception being race twelve at Riverside). At that transition point, Ford already trailed Chevrolet in the points chase since Donahue had scored wins in races two and three, and it’s hard to say if the decision was made as a result of the disappointing standings. Shelby’s Team Manager, Lew Spencer, recounts that the team was “told we couldn’t even open the factory engine crate until a Ford man was there. The whole thing was pretty discouraging, considering our track record the previous years.”

The reality was that the change in engine builders did nothing to improve results, and in fact, the season was soon completely lost to a runaway Penske/Donahue Camaro team. Particularly memorable for futility was the August ’68 race at Continental Divide Raceways, where, as Cantwell recalls, “we blew six engines—two on Friday, two on Saturday, and two on Sunday. It was a mess, and the sense on the team was that Ford’s engine assembly standards left something to be desired. Blown engines went right back to Dearborn without us being able to tear them down.” For the record, the Shelby team won two of the four races in which they prepared the engines (Daytona and Riverside), while Ford-built engines went one for nine (succeeding only at Watkins Glen).

As the quest for a third straight Mustang Trans-Am championship evaporated early in the ’68 season, all accounts indicate Ford quietly abandoned the costly production of the Tunnel Port, particularly with the Boss 302 simultaneously emerging as the race and homologation engine for 1969. No 302 Tunnel Port ever powered a production Mustang, but noted Trans-Am restorer Richard Rodeck says, “I have little doubt that Ford would have put the street Tunnel Port into production had they been in contention for the ’68 championship. The SCCA would’ve put the screws to them if they’d won and didn’t have the engine.”

So how might the 302 Tunnel Port street engine have fared in planned production form? “Not well,” according to Lenox, who explains the effort as “purely for homologation.” Magazines of the day spelled out the mixture for the street engine as follows: dual Autolite four-barrels on an aluminum intake, smog-equipped Tunnel Port heads with 2.01/1.53-inch valves, 10.5:1 compression, Hipo 289-like exhaust manifolds, and a mild hydraulic cam. It was all rated at 240 hp. The juice cam on a high-rpm assembly seems baffling, but then again, how many ’60s performance engines were left in stock form? Despite the high-rev nature, we’d guess there were plenty of Ford enthusiasts who’d have loved to have a shot at a Tunnel Port off the showroom floor. Ordered with a four-speed and 4.11 cogs (or deeper), and with the cam and exhaust replaced by a stout solid-lifter stick and headers, it’s hard to believe this wouldn’t have been the most potent small-block Mustang yet seen.

14/21While articles on the 302 Tunnel Port were prevalent in magazines from 1968, our sister magazine, Car Craft, likely ran more edit than anyone, with spreads in both the February and August issues. Associate Editor Jerry Mallicoat wrote the August piece; he’s seen here (far right) with Ford’s Fran Hernandez (middle) and lead engineer Hank Lenox.

All of this brings us to where the 302 Tunnel Port stands today: a little-known sidebar to Ford’s Total Performance era, prized by enthusiasts more for the concept and commitment it represented rather than for real success. Rodeck opined that in its lone trouble-filled season, “the Tunnel Port really never had a chance for full development since it was essentially abandoned in favor of the Boss 302. The Boss was no doubt better, and production-based as well, which made it pretty compelling. It’s hard to know how the Tunnel Port might have developed given the same two or three years in which most race engines in the series evolved.”

A 302 Tunnel Port sighting is rare today. Your best chance is on the vintage Trans-Am circuit, where drivers like J. Bittle, Bill Ockerlund, and Ross Myers are still revving ’em for all they’re worth, aided by modern valvetrain components that have improved reliability. Factory parts that racers haven’t acquired are generally in the hands of collectors, and the array of pieces that were actually built is pretty amazing. While 40-plus years of history means some elements of the Tunnel Port story are irretrievable, it’s clear this was a project that reflected Ford’s commitment to winning at nearly any cost. That theme was a constant during the Blue Oval’s multi-disciplined racing efforts of the ’60s, and evidence that effort and commitment don’t always play out as planned. Racers know this perhaps better than anyone, and it would seem the ’68 302 Tunnel Port is a textbook example.

Finally, props to a number of people who contributed mightily to helping us unearth a coherent history of the 302 Tunnel Port. In alphabetical order, they include Bill Barr, J. Bittle, Chuck Cantwell, John Craft, Austin Craig, Michael Eisenberg, Donald Farr, Randy Gillis, Hank Lenox, Lee Morse, Bill Ockerlund, Richard Rodeck, Mark Sasko, Lew Spencer, Mark Waco, and John Vermeersch.

18/21This Ford studio shot of the 302 Tunnel Port street engine ran in the Feb. ’68 issue of Car Craft. Shown in what looks to be near-production form, it features dual Autolite four-barrels, Hipo 289-style exhaust manifolds, and full smog equipment. Reality bites, as this engine was never installed in a production vehicle. Hot Rod

Tunnel Port vs. Boss

Comparing a 302 Tunnel Port and Boss 302 head side by side proves interesting. Much has been made of the Tunnel Port’s extreme-high-rpm personality, but the Boss has a similar reputation. Boss heads used bigger valves than a Tunnel Port race head, and its large intake ports have more area—4.375 square inches to 3.8.

19/21

This leads to a logical question: Why did the Boss 302 fare better on the street and track? Engineer Hank Lenox offers at least part of the answer in the layman’s terms that follow: “Beyond the advantage of a canted-valve arrangement, Boss 302s—and traditional Windsors as well—used a Venturi-port design on the intake side. Past the wide initial opening the port narrows, then widens again as it approaches the intake valve. This increases velocity of the airflow, which has a positive effect on low-speed cylinder filling and torque. In contrast, the Tunnel Port is a sewer-port design, with a straight shot that results in a slower charge speed at low rpm.”

Car and Driver “Super Test”

The July ’68 issue of Car and Driver featured a head-to-head test that included what is likely the only street-legal Tunnel Port Mustang ever turned out of FoMoCo—and clearly a prototype effort. The magazine pitted a ’68 Z/28 versus said ’68 Mustang coupe with veteran road racer Sam Posey doing the driving and analysis. Neither car was exactly stock, though it is fair to say the Mustang was at an entirely different level of “not stock,” what with an engine that never made production. Staffers were smitten with both cars, as they featured dual quads, tube headers, and more. Impressively, the Camaro held an edge in most categories, though the Mustang was clearly the visceral choice. This was no street Tunnel Port, described as “your regular 12.5 to one compression ratio, dry deck, Tunnel Port 302.”

Our favorite part of the story is the description of experiencing the Mustang on the street for several days after testing: “It went rumbling and grunting by a Little League game—and broke the whole thing up in the top of the third. The kids had to see what that fire-breathing monster was about. And when we passed a house with a GT350 in the driveway along about 7 p.m., the dining room erupted and people poured out windows, doors, and chimneys. That’s the effect it had. The Mustang even behaved impeccably in one of New York’s patented traffic jams. Every kid on the block had to have a ride in it and wives stood around kind of hoping to fill their prom card. Wild.”

Like so many preproduction efforts, it’s believed that this Mustang went to the crusher.

Rumor Central

There’s no doubt that the 302 Tunnel Port suffered reliability problems during the ’68 Trans-Am season, and we’ve already explained the matter of Shelby versus Ford-built engines. With that in mind, we’ll touch on a story we’ve seen in print elsewhere, and personally heard from several credible sources. It relates to problematic assembly work, and tells of a Shelby mechanic who pulled the rocker covers off a newly installed Tunnel Port from Ford to find some combination of pushrods and rocker arms completely missing. Engineers Hank Lenox and Lee Morse are skeptical such an egregious error could possibly have occurred and, while not being a part of the build team, cited special assembly areas and hot testing for all race motors prior to delivery.

Others who were intimately involved stand by the story, yet offer that the parts were probably pirated sometime after assembly. Regardless, such an experience would obviously further taint an already frustrated Shelby team. Even with assembly practices on the money, 8,500-rpm shifting was bound to have consequences.